Fixed a clang-3.5 missing-prototype warning and added doxygen

documentation for switch_channel_set_presence_data_vals. #doxygen

src/include/switch_channel.h

@@ -165,6 +165,13 @@ SWITCH_DECLARE(switch_status_t) switch_channel_alloc(_In_ switch_channel_t **cha
 SWITCH_DECLARE(switch_status_t) switch_channel_init(switch_channel_t *channel, switch_core_session_t *session, switch_channel_state_t state,
 													switch_channel_flag_t flag);
 
+/*!
+  \brief Takes presence_data_cols as a parameter or as a channel variable and copies them to channel profile variables
+  \param channel the channel on which to set the channel profile variables
+  \param presence_data_cols is a colon separated list of channel variables to copy to channel profile variables
+ */
+SWITCH_DECLARE(void) switch_channel_set_presence_data_vals(switch_channel_t *channel, const char *presence_data_cols);
+
 /*!
   \brief Fire A presence event for the channel
   \param channel the channel to initilize